Throwing, throwing, throwing, as well as throwing from something - the meaning of the word "spew" gives "Explanatory Dictionary of the living Great Russian language" by Vladimir Dahl. However, this is not the only meaning. The same author and the same dictionary expands the meaning of this word: to spew out is to exclude, eliminate, recognizing something or someone as unnecessary, unfit, unworthy. As a result, the semantic load of the word takes on new shades and makes it possible to apply it in a very different context.
Erupting is ...
Here are simple examples: the sea spews amber, and the bowels of the volcano spew lava. Or: general (public) opinion spews (expels) from society . The last example clearly demonstrates the derivation of the word “monster” derived from “spew”. Currently, two of its meanings are common.
"Monster": meaning of the word
First: the outcast is a man cast out of society. For our ancestors, such punishment for wrongdoing to the community was quite widespread. The erupted was forced to lead a vagabond lifestyle (it is unlikely that another community would accept him) and became either a pauper or a criminal. In the recent past, during the time of Tsarist Russia, negligent workers who did not get along with their comrades in craftsmen were expelled from the artisans of artisans after a general meeting.
The second meaning of the word “monster”, which has taken on a negative meaning (probably because of the consequences that led the person to the alienation of society), is a fierce, evil person, a villain. So, King Herod is a biblical monster, tormentor, ruler, who became the culprit of "beating babies." His name is now the household name of the treacherous man who committed the heinous atrocity. Herod was predicted that Jesus would be born and become king of Judah. Then the king, in order to eliminate competition, orders to kill all the babies in the district and thereby protect himself. But Jesus still does not manage to destroy him! With this semantic load, this word (monster, Herod) now has the greatest use.
Another meaning
But there is also an old church, already forgotten meaning: miscarriage, premature baby. This word is borrowed from the Old Slavonic language. In Russian monuments, it appears from the 14th century in the meaning of “rejected”. Its origin is not exactly established. There is an opinion that this is a tracing-paper from the Greek "miscarriage". But some researchers believe it is more likely that the noun "monster" owes its origin to the verb "spew". This word also formed other nouns - “eruption” (of the same volcano), “expulsion” or “throwing out” (lava of a volcano or ash).
In pre-revolutionary Russia
This can also be attributed to those who were used in pre-revolutionary Russia “izverzhenets”, “izverzhenik” - a person deprived of the estate, rank, dignity or throne, expelled from somewhere or expelled. And also a “spout” - one who casts someone, for example from the throne, expels, throws out (some unnecessary thing).
One root
As you can see, the root “verg” is the same for the verb “spew”, and for the noun “monster”. With its help, many other words are formed in the modern language that are close to each other in meaning. Reject, reject - reject, do not accept any point of view, political or social laws. To overthrow - to overturn, to force to fall. To overthrow is to deprive power, to lose the throne.
Related words with the same root can be observed in other languages of the world (the etymological dictionary of the Russian language edited by G.P. Tsyganenko). For example, in Czech - vrhati (throwing, throwing, throwing), in German - werfen (throwing, throwing), in Latin - vergo (twisting, bowing). This also includes Ukrainian "Vergun" (a twisted flour product) and "Verzi" (weaving nonsense, talking nonsense).
But basically, in modern Russian, “spew out” - this primarily means “delete, discard, exclude anything unnecessary.”